


Sister Swap

by Damien_Kova



Category: Hyperdimension Neptunia
Genre: F/F, Multi, Sex Toys, Vaginal Fingering, Yuri
Language: English
Status: Completed
Published: 2019-01-27
Updated: 2019-01-27
Packaged: 2019-10-17 08:35:29
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,000
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17556974
Author URL: https://archiveofourown.org/users/Damien_Kova/pseuds/Damien_Kova
Summary: Noire and Neptune decide to swap sisters for a day, both pairs more than enjoying their time together.





	Sister Swap

Noire couldn’t believe she had agreed to do something like this with Neptune, Nepgear, and Uni. Swapping sisters for a day to see how the other would react when fucked and played with. It was one of the craziest ideas that Neptune had to ever have, but the black-haired cosplayer couldn’t deny the thrill behind the thought of making out with Planeptune’s CPU Candidate. Of course, her mind quickly came back to reality when Nepgear’s lips pulled away from her own, causing the Goddess of Lastation to open her eyes and smile, seeing the flushed cheeks on the pink-haired girl’s cheeks. “You’re that nervous, Nepgear? I thought you of all people would be eager about this just like your sister.~”   
  
The younger of the two let out a soft breath, able to see a glowing tint on the other young woman’s cheeks. “I-I’d rather be doing this with… U-Uni or my sister, but… I’m enjoying it more than I thought…” A soft gasp escaped her lips as she felt two of the black-haired girl’s fingers push into her cunt, her teeth clenching down against her lower lip as the pleasure sparked through her body. “G-Goodness…” Whimpering and whining with each passing second, Nepgear quickly found herself bucking her hips against Noire’s hand, grinding against her lap to try and get as much pleasure as she could.   
  
Noire couldn’t stop herself from chuckling as she starting pumping her fingers back and forth inside of the other girl, finding it incredibly arousing and sweet just how she reacted. It was on a completely different level than Neptune ever reacted, but it was perfect and almost comparable to Uni with the way the gun-wielder always seemed to plead for attention in the middle of their loving sessions. But that didn’t stop the black-haired goddess from rolling the two over so Nepgear was on her stomach and she was laying over her and behind her. “Well, this was your idiot sister’s idea, so we might as well do our best to enjoy it. And those noises you’re making tell me that you’re enjoying yourself more than you wanna let on.~”

 

The sense of satisfaction that was clear as day in Noire’s voices sparked something inside of Nepgrear, causing her to buck her hips and push back against the young woman’s hand. It felt better than she expected it to by a long shot. Even Neptune’s and Uni’s fingers weren’t as slender and long, causing the black-haired girl to reach deeper than anyone else had before with just their hand. Biting into the bed sheets, the pink-haired girl couldn’t stop herself from smiling as the pleasure started to get to her. “Please… More…. More…”

 

Of course, the Lastation CPU knew what she wanted to do with Planeptune’s little sister, a smile on her face as she slowly pulled her fingers out, trailing the arousal-coated digits along Nepgear’s soft thighs. “You want more, Nepgear?~” A devious and almost energetic laugh left the black-haired girl as she suddenly flipped the pink-haired girl over onto her back, watching as her breasts shook and jiggled from the movement. “Then you’ll get it.~”

 

Nepgear gasped and bucked her hips upward off the bed the moment she felt Noire’s tongue drag along her already wet slit, teasing her before circling her clit with it. Her hands immediately darted down and tangled themselves in those black locks that seemed to hover in her lap, gasping and writhing as that talented tongue danced around her sensitive nub. At least, that was until Lastation’s CPU pushed her tongue into her tight hole, causing the pink-haired girl to scream out in bliss as her pleasure only grew. She did want more. Slowly but surely, the CPU candidate was gaining an appreciation for just where Uni learned everything sexual that she knew. “N-No wonder Uni’s tongue is so talented!~” Arching her back, every ounce of pleasure that she was feeling pulsed through her body, causing her to twist on the bed and gasp when Noire pulled back away from her out of nowhere. “B-But….”

 

“Shhh.~” Crawling up Nepgear’s body, placing kiss after kiss along her stomach and modest breasts, Noire finally reached her lips, planting another kiss on her lips. This time, however, she slipped her tongue past the pink-haired girl’s lips, enjoying the way she moaned at the sudden dominant move. Finding herself being usually submissive for those around her, being able to dominate someone other than her own little sister was a thrilling and wonderful experience. It drove her to reach a hand down and slide three fingers into the CPU candidate’s tight, quivering cunt. The moment their lips pulled apart from each other, the CPU went back in for another, so lost in her lust and thrill that she didn’t want to give the young girl a moment to compose herself.

 

And it worked wonders on Nepgear, leaving her so lost in the rush and bliss of the moment that she failed to notice when the two had parted and Noire had gotten off of the bed, the pleasure clouding her mind just a little bit too much. Of course, when she felt the bed shift a second time, her eyes suddenly darted open, a soft but excited whine leaving her when she saw the strap on that was currently hanging between Noire’s legs, admiring just how lifelike it looked. “O-Oh my….”   
  
“Uni and I sometimes like to pretend that I actually have a cock when I bend her over my desk. I thought you’d enjoy that thought as well.~” Before allowing the girl to say anything, Noire adjusted herself to sit between Nepgear’s legs, pressing the plastic dick against the wet and sensitive slit. She didn’t say a word as she started to move her hips back and forth just a little bit, teasing the pink-haired girl as much as she could without actually penetrating her. It was one of her favorite things to do with Uni, and the way the Planeptune candidate reacted only proved to her that it was something that Nepgear liked as well.

 

Nepgear didn’t know just what to do, bringing her hands between her legs and spreading her pussy to show Noire just how much she wanted this. “Please… Fuck me with your cock, Noire…” The blush that tainted her cheeks only got worse as the words left her lips, leaving her begging to be fucked as the black-haired girl only caught her lips in another kiss. She didn’t know what to do, wrapping her arms around the CPU’s neck as she felt the head of the fake cock slip inside of her. There was something sweet and tender about the moment the two were sharing and it made her heart skip a beat as more and more of the faux shaft forced its way into her quivering pussy.

 

However, Noire pulled away from the kiss a moment later and placed her hands on either side of Nepgear’s head, their breasts pressing together as she started to slowly move her hips. She didn’t want to harm the girl or end up going rough right out of the gate, but nothing was stopping the black-haired young woman from smiling as she gazed into the other girl’s eyes. “Does it feel good, Nepgear? Having an eight inch cock inside of you like this?~” Of course, a soft chuckle escaped her as she was answered with a moan, picking up the pace of her hips just a little bit as her nipples rubbed against the pink-haired girl’s. “Good. Enjoy it. I’m not going to stop fucking you until it’s time to send you home.~”

 

Bringing a hand to her lips, Nepgear could only stare up at Noire as she was fucked, her breasts heaving and shaking against the other woman’s with each thrust. It felt far better than she expected it to. She didn’t know if it was her mind playing tricks on her and making her think that the cock was real, but it felt like the member was warm as it filled her up. Gently biting down on her finger, the pink-haired girl’s eyes started to roll into the back of her head as Lastation’s CPU picked up her pace. Even when the black-haired girl sat up, leaving her breasts to shake, jiggle, and sway with each thrust, the tech-junkie couldn’t help but moan in time with each thrust. “It feels so good, Noire!~”   
  
Sitting up straight as she picked up the pace of her thrusts once again, Noire found Nepgear incredibly cute and sexy in her current pose. Finger between her teeth, arm between her breasts, and on her back, completely naked with her breasts swaying with each thrust. It was almost enough to make her want to keep the young girl in her home. Reaching down to caress and play with one of the pink-haired girl’s soft breasts, the Lastation CPU could only smile and relish in the way that Nepgear began to moan and scream with each thrusts. She didn’t know or care if it was because of her thrusts or just because of how she was treating her, as long as that sound continued to fill her ears.

 

On the other hand, Nepgear felt like she was in heaven with each and every thrust that hammered against her womb. Throwing her head back and arching her back as the pleasure started to get more and more intense by the second, the pink-haired girl gasped and whined against her finger as she was fucked into the bed. It felt wonderful, having the faux cock plunge inside of her over and over again, spreading her inner walls and making them quiver with need. Though, she could feel her orgasm rapidly approaching the longer this went on, leaving her feeling needy and sensitive as she gazed up at Noire. “F-Faster…. Harder… I’m going to cum.”   
  
That was all Noire wanted to hear, picking up the pace of her thrusts, getting both faster and rougher with the young girl. Of course, she pinched and twisted the stiff nipple on the breasts she was playing with, throwing in a small bit of pain into the pleasure that she was bringing Nepgear. It didn’t help that she could watch the bliss and ecstasy fill the pink-haired girl’s face as she gave her what she wanted. “Do it, Nepgear. Cum all over my cock and show me how much you’re loving this sister swap idea Neptune came up with. Give me a perfectly good reason to keep you here.~”

 

Arching her back, Nepgear’s orgasm ripped through her body as everything reached its peak. Her inner walls clamped down around the fake cock that filled her over and over again, her teeth clenching down around the finger she kept against her lips to keep herself from screaming out in pure and utter bliss. Of course, it didn’t do a good job of stopping her from squirting, her juices coating Noire’s stomach and leaving her drenched and dripping wet. However, she was unable to actually voice her pleasure when she moved her finger, her lips caught in yet another kiss by the black-haired woman.

 

Immediately starting to move her hips at a much slower and more gentle and loving pace, Noire was happy to have Nepgear’s lips against her own, not caring about the way her stomach was wet with her juices. She was just happy to be there, dominating over the CPU candidate and showing her the best time that she possibly could. Though, it did make her happy to feel the tech junkie reciprocating the affection, moaning against her lips and showing that she loved the immediate second wave of sex. “I told you, Nepgear, I’m not going to stop until it’s time to send you home. I’m going to make you cum over and over and over again until you can’t think straight.~” Of course, the Lastation CPU relished in the excited, arousing, and blissful gasp that escaped the Planeptune candidate’s lips when she said that, causing her to pick up the pace once again.   
  
*************************************************************************************************************

 

With cute little Uni naked in her bare lap, Neptune couldn’t stop herself from giggling as she plunged her fingers into the lithe girl’s sopping pussy, her eyes locked on the black-haired girl’s pleasure-riddled face. “Come on, Uni! I know Noire taught you to be able to handle more than that! You should be able to go a few more hours before cumming!~” The pink-haired girl chuckled as she placed a few kisses all over her friend’s sister’s neck, earning soft and blissful moans from her over and over again. “Or maybe I just feel far better than Noire does.~”   
  
“D-Don’t s-say that…” Uni couldn’t believe the kind of pleasure she was feeling, three fingers all forcing their way into her tight little twat again and again as she was forced to sit there, doing nothing but feeling the pleasure that came to her. It wasn’t anything like the kind of bliss that her big sister brought her, but it was on an almost equal level with just how good and wonderful it felt. The gun-wielder was so used to having her nations CPU bend her over a desk and tease her until she begged for release, wanting to be fucked as hard and as fast as she could. But here she was, given full and ecstatic pleasure from second one and being expected to just there and take it like it was no problem.

 

Neptune could easily feel the young girl’s shaking as she continued to finger her, leaning her head just enough to steal a kiss from her lips, happily pushing her tongue past the girl’s lips and into her mouth. This was what she did with Nepgear and she was able to work up her little sister to the point of having her beg for the pleasure to stop before her mind broke, but being able to see and feel just how Uni reacted was a new but fun experience for Planeptune’s CPU. “Does it feel that good, Uni? Having three fingers buried inside of you like this? I bet you wish it was a cock just hammering away at your pretty pussy.~”

 

The black-haired girl gasped when she felt Neptune’s thumb press against her clit, a jolt of pure and utter arousal coursing through her body, forcing a moan from her lips as she began to slowly rock her hips back and forth against her hand. It felt wonderful to be in her position, another pleasured sound leaving her when her partner for the day pulled her third finger out, allowing the two that remained to reach even deeper inside of her. “N-Neptune…~” Being swapped out with Nepgear for a day or two sounded like an awful idea to start with for Lastation’s CPU Candidate, but it didn’t stop her from loving the position she was in now, especially when her lips met the pink-haired CPU’s for another kiss, this time reciprocating it well and loving every second that their lips danced together.

 

On the other hand, Neptune was just happy to be slowly breaking Uni into being her new little sister. It didn’t quite matter to her if she got to keep Uni or if she just came by for threesomes from this point on, but making the girl understand just how true pleasure felt was what the CPU had in mind for the day. Even as she pulled away and playfully licked as Uni’s lips, she could feel her arousal and lust for her growing. “You come over here quite often to meet with Nepgear. Does she do anything like this with you, Uni? Does she finger you like I do?”   
  
“N-No… Neptune…”   
  
“I bet you wish you could feel this kind of pleasure on top of whatever my adorable little sister gives you, don’t you?~” A soft chuckle escaped Neptune as Uni screamed out in bliss, her inner walls clamping down around her fingers in a powerful and intense orgasm. Of course, the Planeptune CPU kept her fingers moving as much as she possibly could, wanting to make the young girl ride out the experience for as long and as passionately as she possibly could.

 

It didn’t help Uni’s case that her inner walls clenching down made the fingers feel even larger inside of her, like they were reaching deeper than she expected fingers could even go. Though, that thought was quickly wiped from her mind when she felt something plastic press against her lips, her eyes shooting open and allowing her to see the large, thick, black dildo that hovered in front of her. “N-Neptune…? What are you going to do with that?”   
  
“Well, Noire’s able to handle it down her throat easy! Being her little sister, I wondered if you’d be able to do the same!~” A devious and excited chuckle escaped Neptune as she pushed a small portion of the faux cock into Uni’s mouth, listening as the girl panicked for just a moment. “But! Whether you can or you can’t, I’m going to use it to fuck you! Noire loves it when I do that and so does Nepgear! You should too!~”

 

The young girl didn’t know what to say, not that she could say much of anything with the thick member slowly pushing into her mouth. Her jaw actually hurt for a moment from being forced to stretch around the massive thing, her eyes fluttering shut as it pushed deeper and deeper into her mouth. However, the moment the dildo reached her throat, Uni broke into a coughing and gagging fit, unable to contain herself as it reached a spot where she didn’t want or expect it to go. Despite coughing and having her throat sputter around the head of the shaft, the thick member didn’t move, leaving her to endure for a moment and try to push it out with her tongue, incidentally slobbering all over it for a moment until Neptune yanked it out of her mouth.

 

The pink-haired girl adored the harsh gasp for air that Uni made, a smile coming to her face as she pressed the saliva-coated dildo to the girl’s soaking wet slit. “Hope you’re ready, Uni!~” Without any hesitation, Neptune pushed the fake cock inside of the young girl, watching as all eight inches sank into her pussy, filling it and spreading her inner lips right away. Though, she did pause to relish in the loud moan of ecstasy that left the black-haired girl as a result, a chuckle leaving her. “Sounds like you were.~”

 

Right away, the toy began to move inside of Uni, leaving her no real option but to enjoy the pleasure as it washed over her body. However, it was much more intense than the feeling of Neptune’s fingers plunging inside of her, Lastation’s CPU candidate throwing her head back and smiling as everything just seemed to bring her closer and closer to orgasm. Right at this moment, it didn’t matter to her that Noire gave her to Neptune on a bet, or that the two sisters were both getting fucked by the other woman instead of fucking each other. All that mattered to her right now was the feeling of bliss that pulsed through her body with each and every motion of the dildo.

 

Neptune knew this as she pushed the toy back and forth inside of Uni, feeling the resistance of her tight cunt changing depending on how she moved. Even when she pushed the entire toy inside of the young girl, her palm pressing against the black-haired girl’s clit, the CPU didn’t stop herself from moving it. Even going as far as to twist it like a dial while keeping it inside of the young girl. With a smile on her face, the pink-haired girl was more than satisfied keeping the gun-wielder writhing and twisting in her lap the longer this went on, happily stealing another kiss from the young girl’s lips and not caring about the kind of consequences this could have on her relations with Lastation anymore. As far as she cared, the worst it could get was the four getting together for an orgy once a week to relieve some stress, everyone going nuts and just enjoying each other for the entire day.

 

Though, that didn’t seem to ring true for Uni, who leaned upward and placed a deep and passionate kiss on Neptune’s lips, screaming in bliss into it the longer it as the pleasure started to get to be too much for her. Of course, she didn’t bother to stop herself from moaning into the affection when the pink-haired girl’s tongue pushed into her mouth, exploring it once again and making her heart flutter. The black-haired girl knew that she was enjoying this far more than she should, but her mind already too clouded with lust and passion to worry about that. “N-Neptune… Don’t stop… Even when I cum… Don’t stop…”   
  
“Wow, you really do sound like Noire a lot. But you got it, Uni!~” Neptune picked up the pace of her movements, now making the toy plunge inside of her cunt just as quickly as her fingers were earlier, with the now added bonus of turning it inside of her, only adding to both the pain and pleasure that she was feeling. At least that’s what she expected after having doing this to both Noire and Nepgear so much. Though, from just how responsive and appreciate the black-haired CPU Candidate seemed to be, it only seemed like a fair assumption to make on her part. “Cum all you want, Uni. I want you to be unable to think properly when I’m done with you.~” Hearing a soft gasp leave the young girl caused the Planeptune CPU’s lips to curl into a loving smile, happy to hear her enjoying herself so much.

 

On the other hand, Uni could already feel another orgasm rapidly approaching her, her arms reaching upward and curling around Neptune’s neck to keep her close. It felt so intimate and passionate right at this moment that the young girl couldn’t help but smile and gently chew on her lower lip, her heart still fluttering. “N-Neptune… Can I… Stay another day?~” Another sharp gasp left the black-haired girl as the pleasure and ecstasy coursing through her body peaked, her toes curling and her back arching as she came.

 

Neptune watched with a smile on her face as Uni spasmed and twitched in her lap, loving the way she whined as she immediately began to pull the faux shaft out of the tight and quivering cunt. “Does it feel that good, Uni? That you not only want to stay another day but you want to whine when I pull the toy out of you? If I knew you were so receptive, I would’ve told Noire to send you over here years ago.~”

 

Uni could only whine and gasp when the toy finally fully slipped out of her, her body feeling completely empty now. Of course, that was only until the member pressed up against her lips and she gave it a quick lick, able to taste her own sweet and subtle juices on it. “I just… I want more… Noire only teases me. You bring me actual pleasure, Neptune… So does Nepgear…”

 

Neptune thought for a moment as she gently trailed the arousal-coated toy along Uni’s body, down her stomach and toward her thighs. “Well, I guess you can stay another day. On one condition.”   
  
“What is it?! Whatever it is, I’ll make it happen!”   
  
“Once a week, I want the four of us to meet up and have an orgy between all of us. You, me, Nepgear, and Noire. Imagine it. All of us fucking for an entire day and only breaking when we need to eat or rest. If you can make that happen, you can stay as long as you want.”   
  
“Deal! Deal! I’ll do it!~”   
  
“Good. Then let’s continue.~”


End file.
